Seal tightening for centrifugal machines



l Parenteel Feb.1o, 1931 UNITED STATES PATENT oFFlc-'E GEORG STAUIBER,OF BERLIN, GERMANY SEAL '.lIGrH'lENINGrl FOR CENTRIFUGAL MACHINESApplication led' October 6, 1927, vSerial No.

`In rotary or centrifugal machines appreciable clearance losses areproduced between the rotating wheels and the casing'. In order to reducethese losses the clearance between the wheel and casing may be reducedin a known manner-as by a flexible sliding riable liquid pressure. inthe passage of the discharging liquid and ofthe counter-acting theclearance walls,

forces automatically adjusts itself to the smallest' clearance opening.

The-'object of the present invention is to reduce the losses in a moreeffective way than has been possible by the devices heretofore known,andthe invention consists in that of which one is movable withrelation tothe other in the direction of the enlargement or reduction of theclearance, is so formed that the clearance cross section is continuallyreduced in the direction of liow of the clearance liquid. By thisconstruction a much higher eiiciency is obtained than with parallelclearances. Consequently, eration it will be possible to adjust theclearance much more accurately and to thus maintain the water losses farless than in the case of the known arrangement of clearances withparallel walls.

In the accompanying drawing wherein the invention is illustrated thefigure is a detail section showing the invention applied to use.

Referring to the drawing in detail the numeral 1 indicates the wheel, 2the casing and 3 the clearance between them to be sealed.

The tightening is effected by a packing ring 4 which according to theinvention is of a special form and bymeans of which the continuousreduction in the clearance space -pressure is highest when with the sameeffectiveness in opl-- 224,495, and in Germany October 13, 1926.

is obtained. The form in the embodiment illustrated is such that whenthe counter surface at the runner is flat the side of the ring opposedto said surface is so taperedthat it may -only bear against the runneralong a circular line so that between the ring andthe runner acontracting passage 6 is formed, this form being further characterizedin that between the .side of the ring in front of the casing and thecasing itself a 'pressure space 5 is provided. The spaces 5 and 6communicate with each other and with the clearance Sto be sealed. In thepressure space 5 there exists a substantially constantpressure dependentupon the different clearance pressures at the circumference of theIclearance space 3. ,The l'ire'ssure4 space 5 opposite the casing wall 2is elastica'llysealed by a ring 7 other suitable material. Inlthelpassag'e 6 approximately the same .pressure 1 exists as in the space5 provided the ring 4 fits the wall l so closely that no water flowsbetween them. By the contraction or reduction of thepassage '.6outwardly, which is an important factor in proper packing, the pressureacting upon the tapered wall ofthe packing ring located on the runnerside is highly variable, and in such manner that the the packing ring 4closely Hfits the runner 1 and steadily decreases the fartherl thepacking ring is removed from said runner.

Since the counter pressure exerted by the liquid in the space 5 upon thering 4 remains substantially constant, the packing ring w1ll remain in astate ofequilibriumin that position in which the pressure on the side ofthe clearance balances the pressure of the liquid in the space 5 and thespring forces act in the same direction where such are present.

If the packing ring 4 tends to approach side of the clearance upon thepacking ring surrounded by adouble, ring'f'8 of rubber. or

lthe runner wheel l, the quantity of the dis- 4 so that the packing ringis displaced from the runner.

Thus the free movability of the ring 4 is essential for the mode ofoperation of the device, and this ring therefore must be fastened to thecasing in such manner that it may freely adjust itself in the way aboveset forth. As herein shown, this adJustment is permitted by suitablesprings arranged on bolts loosely holding the ring 4 in attachedrelation to the casing 2, one of said springs being indicated at 9.

By means of the sealing device according to the invention it is notintended to produce a condition in which no Awater whatever dis\ chargesbetween the runner wheel and the packing ring. This condition wouldresult with wear of the ring 4 and in corrosion of the fiange of thewheel. It is intended, on the contrary, by shaping the packingring 4 toenable the discharge and waste of a certain quantity of water betweenthe runner and the packing ring, but only as much as will be necessaryto obtain effective liquid lubrication between the wheel and the ringand to avoid mutual wear. This intentionally caused loss of waterobviously involves a loss of energy which, however, is substantiallylower than that which results with other types of sealing devices.

The load surfaces on both sides of the ring 4 are so dimensioned thatthe packing ring in the position of equilibrium closely approaches therunner wheel, thus permitting a slight water discharge, suiicient,however to leave an adequate layer of lubrication between the runner andthe packing ring and to prevent mutual wear of the latter.

The characteristic of the invention is the shaping of the clearancewalls in such manner that aclearance contracting or decreasin in' thedirection of ow is formed.

claim:

1. In a fluid pressure turbine having a casing and rotor mounted'thereinprovided with a runner clearance sealing means between the runner andthe casing including a ring interposed between one side of the runnerand the casing, the opposing side faces of the runner and the ring beingspaced apart to provide a y clearance passage therebetween and said ringhaving a single circular line of contact with the face of the runner atthe outer side of said clearance passage, and means for yieldinglymounting said ring upon the casing whereby said ring is mova lyresponsive to variable iluid pressures in the clearance passage.

2. In a'iiuid pressure turbine having a casing and rotor mounted thereinprovided with a runner; clearance sealing means between the runner andthe casing including a ring interposed between one side of the runnerand the casing, the opposing side faces of the runner and the ring'beingspaced apart to provide a clearance passage therebetween and mountingsai ring upon the casf casing at the outer side of said pressurechamber.

3. A fluid pressure turbine having a casing and a rotor mounted thereinprovided with a runner, a sealing ring, and means, for movably mountingsaid ring upon the casing for movement towards and from one side of therunner, the said side face of the runner and the opposing' side face ofthe ring extending in convergent relation to each otherV to provide aclearance passage gradually diminishing in cross sectional area towardsthe discharge side of said assage, and said ring at the dischar e sideoi) the passa e having a single line o circular contact with the sideface of the runner, and said ring moving relative to thev runner toincrease the area of the clearance discharge in corespovndence withincrements of increase of uid pressure in the clearance passage.

In testimony whereof I have signed my name tothis specification.

DR. GEORG STAUBER.

